CVE-2026-23873

9.0 CRITICAL
Published: January 22, 2026 Modified: February 27, 2026
View on NVD

Description

hustoj is an open source online judge based on PHP/C++/MySQL/Linux for ACM/ICPC and NOIP training. All versions are vulnerable to CSV Injection (Formula Injection) through the contest rank export functionality (contestrank.xls.php and admin/ranklist_export.php). The application fails to sanitize user-supplied input (specifically the "Nickname" field) before exporting it to an .xls file (which renders as an HTML table but is opened by Excel). If a malicious user sets their nickname to an Excel formula when an administrator exports and opens the rank list in Microsoft Excel, the formula will be executed. This can lead to arbitrary command execution (RCE) on the administrator's machine or data exfiltration. A fix was not available at the time of publication.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/zhblue/hustoj/security/advisories/GHSA-gqwv-v7vx-2qjw
Source: security-advisories@github.com
Exploit Mitigation Vendor Advisory

1 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.0 / 10.0
EPSS (Exploit Probability)
0.0%
5th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

hustoj